Chromatography Forum

Hello all,

The work that I am doing with regards to HPLC analysis involves looking at preservative levels in paints and latices. The sample prep method that I have is only a liquid-liquid extraction (0.2g of paint/latex dissolved in 15grams of H2O.) I filter every sample through a 0.2um filter but still get a ton a backpressure after about 20-30 injections. I am using a guard column as a precaution but at the rate I am going I am burning through 3-4 guard columns a month. The molecule I am looking at is extremely hydrophilic so I can't really use a strong solvent during sample prep. Any suggestions on what I should do??

Thanks.

B

Take your sample after Filtration into a vial and a while into the freezer. Than use a centrifuge and take only the clear solution on the top.
Second alternative is to clean again on a C18 SPE cartridge before HPLC.
Hope that will help.

Ok I'll give that a try. How long should I leave it in the freezer? Half hour? Would it make sense to centrifuge the sample, filter, freezer and then sample again?

15 to 20 minutes schould be ok. First filter, freezer and than centrifuge. Good luck